Frequently asked questions for

Powder Coatings

Here are some of the most frequently asked questions with their answers from Powder Coatings.

 

What is your general recommendation of anti-crater and flow & leveling additives in powder coatings?

Our products BYK-360 P / BYK-368 P and BYK-3900 P are well known in the market as anti-crater and flow & leveling additives for all resin systems and all formulations. The typical dosage on total formulation is app. 1,0% as starting point.

How can we improve our manufacturing processes to get higher throughput in extrusion but also better batch-to-batch consistency?

Manufacturing process is strongly dependent on equipment and all related parameters. In case of not optimized processing parameters, not optimized formulations or not optimized and older equipment, our processing additives will help. BYK-3950 P is a general working additive to improve processing and throughput in all systems. BYK-3951 P is more specialized for TiO2 containing formulations. BYK-3955 P is highly recommended for all formulations with carbon black pigments. All these additives will also improve batch-to-batch consistency.

We often observe small craters in our powder coatings. Some formulations are more crater-sensitive in production and some other formulations are more critical in final application at our customers. Is there any additive to avoid craters and to improve cross-contamination between different powder coatings?

BYK-3931 P will increase the anti-crater efficiency of your standard leveling additive. BYK-3931 P​​​​​​​ should be used as a synergist in combination with each other standard leveling additive. Additionally it can help to reduce cross-contamination problems between different powder coatings. In general it will increase the crater-robustness in all resin systems.

Is there any dispersing additive available for improved pigment-wetting, specifically for organic pigments?

Within our processing additive range we also have wetting and dispersing additives for powder coatings. The solid delivery form of DISPERBYK-2200 and DISPERBYK-2205 offers easy handling in powder coatings. Both additives will improve dispersing of specifically organic pigments and carbon black pigments. Improved color-strength is the result of better pigment dispersing.

Fine texture or structure effects from smooth surfaces down to deep-matt gloss levels are very common in the market. What is your recommendation for fine textures in a variable gloss range?

The range of PTFE based wax additives will cover the whole range of requirements in this case. CERAFLOUR-959 as a PE/PTFE combination provides smooth and semi matt texture effects. CERAFLOUR-955 as pure and EU REACh compliant PTFE is used for deep-matt texture finishes.

I heard about REACh problems with PTFE due to it´s PFOA content. Do you have REACh compliant PTFE additives available in your portfolio?

All our PTFE based wax additives are EU REACh compliant and contain less than 25ppb PFOA.

In case of PTFE containing texture and structure powder coatings, what is your recommendation to reduce the PTFE content in the formulation?

PTFE wax additives still offer the highest efficiency to create texture and structure effects. But a PTFE-reduction is possible by adding rheology additives to the formulation. A higher melt viscosity will overcome the reduced PTFE texture effect and can be used to adjust the optical appearance. CLAYTONE-HY or CLAYTONE-40 are our standard recommendations in this case.

What kind of additive do you recommend for structure finishes with bold pattern or a hammertone effect similar to CAB?

CERAFLOUR-967 will create a nice structure effect and can be combined with effect pigments to achieve a robust hammertone. There are guideline formulations available on request.

In HAA systems we have problems at higher thicknesses with pinholes, how can we avoid this?

Degassing of HAA systems is a typical problem at higher thicknesses. CERAFLOUR-960 is our standard recommendation in this case. For all low-bake systems and high gloss systems we recommend CERAFLOUR-964 as non-blooming degassing additive.

How can we avoid surface defects like blisters and bubles caused by outgassing on porous substrates?

For improved outgassing in all systems on critical substrates like galvanized steel, we recommend CERAFLOUR-961. This wax additive is used in extrusion process. In case of post-addition we recommend CERAFLOUR-962. This additive can be blended with ready made powder coatings.

How can we improve the recoatability of our powder primers with liquid coatings?

Recoatability is dependent on wetting properties and this is related to surface-tension, respectively surface-energy. A higher surface energy of the primer will lead to better wetting properties and recoatability. Therefore we recommend BYK-3933 P in such primer formulations. BYK-3933 P will increase the surface energy of the cured powder coat surface.

We have some problems with intercoat adhesion due to blooming effects. What can you recommend to avoid this?

Blooming is often caused by the migration of wax additives to the surface. In case of degassing we recommend CERAFLOUR-964. This wax additive is blooming-free and will also not reduce gloss levels.

How can we improve scratch resistance?

BYK-3932 P helps in many cases to protect the surface against scratches. BYK-3932 P provides high slip properties and this will avoid scratches in all systems but especially in metallic powder coatings based on leafing aluminum pigments. Another option is CERAFLOUR-996 R as wax additive. The combination of PE and PTFE protects the surface also against stronger forces and offers both, scratch- and abrasion-resistance.

How can we improve abrasion resistance?

Our standard recommendation is CERAFLOUR-996 R as PE/PTFE combination. The containing PTFE particles will strongly increase abrasion-resistance. In case of high gloss systems CERAFLOUR-981 R as pure PTFE can be used as well.

There are more and more critical substrates and less good cleaning processes in some areas of the market. Also not optimized pretreatment leads to less good substrate-wetting properties of the powder coat layer on such substrates. Is there any kind of adhesion promoter or any other additive available to improve substrate-wetting and adhesion?

BYK-364 P used as leveling additive in the formulation provides a higher polarity and this leads to improved substrate-wetting of powder coatings. For improved adhesion we have some other possibilities to recommend case by case - please get in contact with our technical service team.

What is your recommendation for thin film thickness powder coatings?

BYK-3902 P as leveling additive offers high efficiency at low film thicknesses below 50µ and at higher thicknesses it works well as a standard leveling additive.

What is your recommendation for low-bake systems, typical curing temperature below 150°C.

As standard leveling additive we recommend BYK-3900 P as most suitable in low bake systems. As degassing additive in low bake HAA systems our CERAFLOUR-964 will eleminate pinholes.

Is there any additive for gloss reduction in your portfolio?

For gloss-reduction we can recommend some of our wax additives. The stronges efficiency offers CERAFLOUR-970. This PP wax will also provide anti-slip properties. Our PE wax CERAFLOUR-950 will also help to adjust gloss levels. Both wax additives offer also good non-blooming properties to keep the achieved gloss levels in a stable range.

We need high corrosion resistance and edge-coverage, what do you recommend?

Edge-coverage is dependent on viscosity and will be improved by higher melt-viscosity. With our rheology additives CLAYTONE and GARAMITE we offer a wide range of different possibilities. Please contact our technical service team for more detailed recommendations.